Greenhouse gases are gases that trap heat in the Earth’s atmosphere. They allow sunlight to travel through the atmosphere, but they keep the heat that the sunshine generates from leaving. 

Greenhouse gases are mainly made up of Carbon dioxide (CO2), methane (CH4), nitrous oxide (NO), and water vapor are the principal gases responsible for the greenhouse effect, as are fluorinated gases. 

These gases entrap heat in the atmosphere and contribute significantly to temperature rise and global warming

Greenhouse gases have distinct chemical characteristics and are eliminated from the atmosphere through various processes over time. 

Anthropogenic activity affects global climate via interfering with energy fluxes through changes in atmospheric gas composition rather than the actual generation of heat due to energy use.

Main GreenHouse Gases

1. Carbon Dioxide

Carbon emission by sectors
Carbon emission by sectors | Image Credit – Research Gate

Carbon dioxide (CO2) is emitted by burning hydrocarbon fuels like gasoline, coal, natural gas, wood, and oil. 

Due to human activities, carbon dioxide is added to the atmosphere. These fossil fuels comprise carbon, and when they are scorched, they combine with oxygen, forming carbon dioxide. 

The World Energy Council notified that global carbon dioxide emissions from burning fossil fuels rose 12% between 1990 and 1995. 

The growth from developing nations was three times that from developed countries. 

The Middle East carbon dioxide emissions from the burning of fossil fuels increased 35%, Africa increased 12%, and Eastern Europe increased rates by 75% from 1990-1995.

The leading natural carbon sinks are forest and wooded areas, where trees absorb carbon dioxide and release oxygen. 

Due to deforestation, carbon released into the air stays in the atmosphere, where it bonds with oxygen to form carbon dioxide, which adds to the greenhouse effect. 

Due to an overload of chemical and reactive substrates, it is resulting in an imbalance in the sink: source carbon ratio. Furthermore, as CO2 levels rise, the energetic cost of carbohydrate exports rises.

Many industrial operations emit CO2 due to the use of fossil fuels. Several processes emit CO2 through chemical reactions that do not involve combustion, such as the manufacture of mineral products such as cement, the manufacture of metals such as iron and steel, and the manufacture of chemicals.

The most effective way to reduce carbon dioxide gas is by minimizing fossil fuel consumption. Improving building insulation, driving more fuel-efficient automobiles, and using more energy-efficient electrical equipment are all strategies to reduce energy use and CO2 emissions. 

A recent study found increased CO2 promotes photosynthesis in C3 species such as rice, soybean, and wheat. On the other hand, they warned that enhanced CO2 could cause negative feedback of photosynthesis.

The increased CO2 had a “fertilization” impact because crops increased their photosynthetic and stomatal conductance in response to increased CO2. 

Additionally, we can reduce personal energy use by turning off lights and electronics when not in use, which minimizes electricity demand. 

Reducing vehicle distance traveled reduces gasoline use. Both are methods of lowering CO2 emissions from energy consumption.

2. Methane

Methane emission in total
Methane emission in total | Image Credit – Wikimedia Commons

The primary organic trace gas in the atmosphere is methane (CH4). CH4 is a significant component of natural gas, which is used as fuel worldwide.

A methane molecule is assembled by the breakdown or decay of organic material. It can enter the atmosphere through natural processes such as the decay of plant material in wetlands, the seepage of gas from underground deposits, the digestion of food by cattle, or human activities such as oil and gas production, rice farming, or waste management. 

Also, methane is produced and transported as a byproduct of coal, natural gas, and oil mining and transportation.

The second most influential anthropogenic greenhouse gas is methane after carbon dioxide. It has an indirect effect on climate through chemical feedback

Anthropogenic methane emissions account for more than half of current worldwide methane emissions, with the main contributors being fossil fuel production, ruminants, rice farming, and waste disposal. 

Methane has a far shorter lifetime in the atmosphere than carbon dioxide (CO2), yet CH4 is more efficient at trapping radiation than CO2. 

Over 100 years, the comparative impact of CH4 is 25 times greater than that of CO2.

Agriculture is an essential source. Domestic livestock, like cattle, swine, sheep, and goats, create CH4 naturally as part of their digestive processes. 

In addition, CH4 is created when animal dung is stored or managed in lagoons or holding tanks. Natural gas is primarily composed of methane. 

Methane is discharged into the atmosphere during natural gas production, processing, storage, transmission, distribution, and crude oil production, refinement, transportation, and storage. Also, Coal mining contributes to CH4 emissions.

There are multiple methods for reducing greenhouse gas emissions from the industrial sector, including energy efficiency, fuel switching, combined heat and power, the use of renewable energy, and more effective material usage and recycling. 

Also, methane from coal mines can be captured and used for energy. We can reduce gas emissions from oil and gas production by adopting gas injection and on-site power generation technologies.

3. Nitrous Oxide

Overview of U.S. Nitrogen oxide gas emission in 2019
Overview of U.S. Nitrogen oxide gas emission in 2019 | Image Credit – United states Environmental Protection Agency

Nitrous oxide (N2O) is a potent greenhouse gas. It is estimated to contribute about 6% of the global warming effect due to greenhouse gases. 

In the Stratosphere (a layer of the earth’s atmosphere), N2O is oxidized to form NO and NO2.  

These nitrous oxide catalyze the destruction of ozone, making N2O the single most crucial ozone-depleting emission in the twenty-first century. 

Medically, Nitrous oxide has been used as an anesthetic and an analgesic for more than 100 years. It is appreciated for its anti-anxiety effect. 

Also, it is a laughing gas that activates parts of the brain’s reward system. This purpose leads to a euphoric effect.

Nitrous oxide is emitted during agricultural, land use, industrial, fossil fuel and solid waste combustion, and wastewater treatment. 

Agricultural soil assessment is the most significant source of N2O emissions in the United States, accounting for over 75% of total N2O emissions in 2019

In Addition to N2O emissions from agriculture, there are indirect emissions, such as those caused by the leaching of nitrogen from agricultural fields to aquatic systems, which increase N20 emissions from rivers. 

Furthermore, natural systems can act as important sources and sinks of N20. IPCC (2013) revealed that about 40% of total NO2 emissions come from human activities.

Their global emissions have increased over the last century, owing primarily to human influence. 

The soil emits both N2O and NO. N2O is a significant GHG, whereas NO indirectly contributes to O3 production. 

N2O can be 300 times more potent than CO2 as a greenhouse gas. The former, once in the stratosphere, catalyzes the removal of O3.

We can minimize emissions by reducing nitrogen-based fertilizer applications, applying these fertilizers more efficiently, and changing farm manure management methods. 

Additionally, Pollution control devices (for example, catalytic converters to reduce exhaust pollutants from passenger cars) can also help to minimize N2O emissions. 

Because nitrous oxide is primarily emitted from industry through the combustion of fossil fuels, technological advancements and fuel switching are efficient methods of reducing N2O emissions from industry.

4. Fluorinated Gas

Fluorinated greenhouse gases contribute approximately 2% of global greenhouse gas emissions.

These gases are a class of artificial gases used in various industrial applications, primarily as substances such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons, which are being sometimes used as substitutes for stratospheric ozone-depleting substances.  

The constantly expanding demand for refrigeration and cooling services, particularly in emerging nations, promises to increase Fluorinated gas emissions in the coming decades significantly. 

Many Fluorinated gases contribute significantly to global warming. As a result, modest air concentrations can substantially impact global temperatures. 

They can also have extensive atmospheric lives, extending thousands of years in some situations. 

Like other long-lived greenhouse gases, most fluorinated gases are well-mixed in the atmosphere and spread over the planet when they are emitted.

Unlike many other greenhouse gases, Fluorinated gases have no natural sources and are only produced by human activity.

Greenhouse effect

Greenhouse Effects | Video Credits – NASA Space Place

The greenhouse effect is a natural mechanism that raises the temperature of the Earth’s surface. 

When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected in space, while the remainder is absorbed and re-radiated by greenhouse gases. 

The atmosphere of the Earth contains different gases like carbon dioxide, nitrous oxide, methane sulfur dioxide, chlorofluorocarbon, hydrofluorocarbon, ozone, water vapor, etc. 

The atmosphere containing such gases covers the Earth and acts as a glass or plastic of artificial greenhouse. 

Solar radiations of short wavelengths easily enter the Earth through the atmosphere and strike on the surface.

The radiation having a long wavelength cannot return to space. These radiations that have long-wavelength can’t return to space because these radiations are absorbed by the atmosphere. 

By this process, heat received from the sun is trapped on the Earth’s surface, resulting in an increased temperature. 

Such an effect is called the greenhouse effect. Any gas capable of observing infrared radiation emitted from the Earth’s surface and reradiating it black to the Earth’s surface contributes to the greenhouse effect. 

Without the greenhouse consequence, the average temperature on Earth’s surface is expected to be estimated at -19°C, rather than the present average of 14°C.

Conclusion

The greenhouse effect is the primary driver of climate change. Some gases (CO2, CH4, NO2, and fluorinated gases) in the Earth’s atmosphere operate like glass in a greenhouse, keeping the sun’s heat and preventing it from leaking back into space and creating global warming. 

Furthermore, global warming will cause climate change, such as increased CO2, rising temperatures, and changing precipitation, dramatically impacting natural ecosystems, such as vegetation function, sustainable food production, and crop yields. 

One of the most effective strategies to combat global warming is transitioning away from fossil fuels and toward renewable energy sources such as solar, geothermal, wind, and biomass. 

Although not yet an international consensus, there is widespread agreement that climate change results from anthropogenic sources of greenhouse gasses (GHG) emissions.

Previous studies have significantly reported the effect of greenhouse gases; however, the pragmatic solutions for mitigating such gases are still minimal. 

Further studies are required to control greenhouse gas emission factors from different agroecological zones considering different soil types, crop management practices, and climatic conditions to respond to this issue policy.

Ranjana Regmi is a highly energetic and responsible graduate with a master’s degree in Environment Science. She has a sound academic and professional record of exploring the world of climate change and its dynamics related to vegetation and wildlife. She has developed analytical skills during a few years of work exposure and scientific coherence. She is undoubtedly a bright star for ecosystem preservation with an immense empathy towards biodiversity.